The Thermarest RidgeRest SOLite Mattress provides the lightest comfort possible and can boost the warmth and durability of a three-season mattress for winter use. With the patent-pending aluminized Solar coating, the RidgeRest SOLite offers a 10% boost in warmth with even more durability from surface wear and tear. All of this with no appreciable weight gain makes it perfect for everything from extreme, high-altitude climbing to entry-level backpacking.